Furnace



c u I u 600006000000 Wlmlml April 26 1927.

A. J. M. A. R. VAN DER Doss DE BIJE FURNACE Filed A112. 1923 J1.1113.11. van durum JeByc 5 of the United States of ed to advancePatented Apr. 26, 1 927;

. UNITED" STAT Es PATENT o r 1,625,954 FFICE,

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Application filed August 15, 1923.: Serial No. 657,591.

This invention relates to improvements in furnaces, and particularly toimprovements in furnaces having a mechanical stoker of the type patentedto me by Letters Patent America, 389, and comprising as essentialelementsa grate portion having a large draft capacity, another grateportionhaving a much lower. draft capacity, an under-feed device adaptthe fire bed onthe grate portion with a large draft capacity, and meansfor supplying supp-lementary air 'to the combustion chamber above thefire bed.

The principal object of 'my present inii vention is a furnace grate ofthis type which is of a more simple constructio In the furnace describedin the said patent specification means are provided for dis charging theashes and clinker from the Q grate at the rear end thereof. Meanwhile ithas proved in practice that ash traps the fire bottom give riseto.leakage of air from the ash pit to the fire bed; This air mayseriously impair the efficiency of the i furnace as it enters the firebed where the draft capacity of the grate should be very low or zero. 1

' New I have foundthat the ashes in .a

furnace of said type bake or cake to clinker w and that this clinker mayfrom time to time :frontL Furthermore I have found that this' f Figure Iis a. vertical section of a.furnace be withdrawn by a fire door in thefurnace simple arrangement alsd allows of the provision ofanunsymmetrical grate, in which the areawith a large draft capacity isdis-. posed atone side of the grate. The clinker in. such a furnaceautomatically moves to a part of the grate whence it can be removed 46through a door in the front of the furnace by means of an 'rdinary firehook or rake.

In the accompanying drawings-- according to. the invention taken on theFigure '2 is a; plan viewsmall blow holesforthe air which is forced so.distributed over 'ing door 14, the ash pit the ram or-plunger 26forward- -ward.

line 1-.1 of Fig. 2. Surrounding parts have not been shown as these arenot emential;

Figure 3 .show s the front of the furnace;

into thespace below the fire bottom, said space belng enclosed by acurvedplate 6,- part of the fire'bridgecasting 7, and by the front ashpit door 8. The apertures in the grate port on 9 are so dimensioned andsaid portion that the coal receives a suitable quantity of air. It hasbeen found thatccal after having lost its gaseous constituents and afterbeing converted into coke should be hurntdown more slowly if a highefiiciency isto be attained, so* that at the end and at the sidt's ofthe fire bottom hardly any primary air should be fed to the fire bed.

The front of the furnace is formed bya cast iron frame l0'supporting acoal hopper 11 and provided with a door 12 forp-reventing coal fromdropping from the furnacewhile raking the grate, a fire door 13 with asmall'sightidoor there above and the pokdoor 8, and a con nection 15connected with the air tube 16, the latter being equipped with a valveoperated'by means of a'handle 17 Arranged in the upper part of thecasting 10 is a cavity with a nozzle 18 for blow ing secondarycombustion air over .the fire bed 19. The air is fed intb said cavitythrough a tube 20 provided with a regulating valve 21 and branched fromtube 16.

The frame 10 also serves to support a frame 22, mountd which is areciprocating gear (not shown) driven by a pulley 23 keyed on a shaft 24and importingrotary movementto a screw spindle .25. in either the oneort-he other direction so as to move or back- The ram 26 isste pedas at2'2. Duringthe return stroke of the/ram fresh cdal from the hopper 11falls by gravity on the ram'in front of said step, and during theforward stroke-of the ram this 00211 is pushed .under the fuel 13already on the fire bottom.- The end portion 28, of the'ram is bevelledat one side as at 29, so that during the forward stroke of the ram thegreater part of the coal and clinker resting on the fire bottom iscarried forward,the smaller'part being pushed sideways so that the fuel1 is uniformly distributed over the fire bottom. 5

Experience-has shown that. a cast'iron ramcan operate for a. long timebefore it requires renewal. As it is notnecessary forkv the end portion28 to be completelywi-thdrawn from the fuel on the -fire t\ottom,'thef la travel of the ram may be reduced to aminimum. The movement of the ramthrough manner similar to whatis known in ordlnary furnaces for thepurpose of smoke combustion, mixes up with the gases which are producedfrom the coal immediately after the coal has been fed onto the firebottom, and this mixture of combustible gases and air contacts with thehot flames above the bar section 5 so that it is burnt very completely.The air, which is not used for burning the gases is consumed by the redhot coke distributed over the rear end and the side portions of the firebottom. This system of burning fuel has given very satisfactory results.v

The 'mple construction of the furnace renders it fit for use in thefiues'of ordinary Scotch marine boilers and the like.

During the operation of the furnace a certain quantity of clinkeraccumulates at the end and another quantity collects upon the plateportion of the fire bottom. These quantities depend upon the quality ofthe coal; with fuel of ordinary quality the clinker should be removedabout every eight or twelve hours. The fact that the fire bottom is fiatfacilitates the discharge of the clinker.

The simple construction of the fire bottom feed ram arranged at one sideof the longitudinal axis of the furnace and adapted to advance 'the firebed on the area with a large draft capacity, means for supplyingsupplementary air abovethe fire bed, a fire door disposed III.

a poking hole in the furnace front at the other side thereof in respectto the ram.

2. In a furnace, a fire bottom including a bar grate portion and a plategrate portion, both grate portions in their entirety bein arranged inthe same plane, a feed ram slid able over the bar grate portion of thefire bottom and a nozzle arranged above the fire on the fire bottom forsupplying supplementary air above the fire bed.

3. A furnace as claimed in claim 2 characterized by the arrangement ofthe bar grate portion and'ram at one side of the center of the firebottom.

In testimony whereof I afiix my signature.

ANNE JACOBUS IATHYS AUGUST RIDDER an der DOES de BUB.

the furnace front at the wide side thereof in respect to the ram, and

